As the Monument Valley (video game) was made available for free on iOS platform (usually for a limited time only), this shopkeeper downloaded the award-winning game. He was very impressed- the interactiveness, story-telling etc. Most of all, its graphic design in reference to M. C. Escher's works.

For comparison, here are the images from the game and Escher's work, Waterfall taken from a Pop-Up book (which of course is on sale in this bookstore :)

Do check out the game, whether you are on iOS platform or not. Beside it being an enjoyable game, it might even tell us something about changing perspectives to see things differently.